The present invention relates to a punch press which makes holes in a plate material and forms it after moving the plate material to a punching process part.
An NC unit usually controls the punch press to punch the plate material after stopping it at the predetermined process position, however the cycle time becomes longer and the hit rate becomes lower if waiting for the plate material to be completely stopped.
As illustrated in a plate material transfer speed and a motor speed in driving a ram of FIG. 9, the punch motion is started and the punch goes down before a table unit stops to transfer the plate material for improving the above problem. Additionally, as illustrated in a crank angle of FIG. 8, this is an example of reciprocating a crank mechanism. The crank mechanism is reciprocated between a waiting position HH1xe2x80x2 in front of contacting a punch tool with the plate material and a pullout position HH2xe2x80x2 wherein the punch tool is apart from the plate material after punching through a bottom dead center BDC but it does not pass through a top dead center TDC.
There is a problem in the above control that the ram must be accelerated rapidly and the energy in driving the motor is increased though the hit rate is improved.
It is an object of the present invention to provide a punch press which can realize high hit rate and energy saving in a punch drive.
It is another object of the present invention to realize high hit rate and energy saving by the simple control wherein the calculation load in a control system is low.
It is a further object of the present invention that a ram can move up and down smoothly when not punching and it excels at absorbing vibration and shock.
It is an additional object of the present invention to provide a plate material transfer/punch motion control program which can realize high hit rate and energy saving in the punch drive.
The present invention will be described with reference to FIG. 1 corresponding to a preferred embodiment of the present invention. This punch press makes holes and/or forms with a punch tool 6. This punch press comprises a plate material transfer means 3 for transferring a plate material W, a punch drive means 9 having a rotational/linear motion conversion mechanism 20 that converts the rotation of a servomotor 19 into the rise and fall of a ram 8 which makes the servomotor 19 a driving force and moves the punch tool 6 up and down by the ram 8, a plate material transfer control means 32 which controls the plate material transfer means 3, and a ram axis control means 33 which controls the punch drive means 9.
The plate material transfer control means 32 controls the plate material transfer means 3 so as to start to transfer the plate material when the punch tool 6 moves up to a pullout height HH2 not contacting with the plate material W after punching the plate material W.
The ram axis control means 33 rotates the servomotor 19 in one direction, the punch tool 6 is controlled so as to reach a height HH1 which is likely to contact with the plate material when the plate material transfer means 3 completes to transfer the plate material and a motor speed pattern VP that is a rotating speed pattern of the servomotor 19 when the punch tool 6 goes up from the non-contact pullout height HH2 to the height HH1 which is likely to contact with the plate material through a top dead center TDC is generated based on a distance D of transferring the plate material, in said pattern the motor speed not being zero when the distance D of transferring the plate material is under the predetermined distance. Additionally in the motor speed pattern VP, it is preferable to come to the set speed in order for the punch tool 6 to punch when the plate material is completed to transfer and the punch tool 6 reaches the height HH1 which is likely to contact with the plate material. The rotational/linear motion conversion mechanism 20 is a crank mechanism and an eccentric cam mechanism, for example.
According to this configuration, the plate material transfer control means 32 and the ram axis control means 33 starts to transfer the plate material W when the punch tool 6 goes up to the pullout height HH2 not contact with the plate material W and the plate material transfer means 3 and the ram axis control means 33 are controlled synchronously such that the punch tool 6 reaches the height HH1 which is likely to contact with the plate material when completing transferring the plate material, so that the unnecessary waiting time is not produced and the hit rate is improved. Moreover, the ram axis control means 33 rotates the servomotor 19 in one direction and the motor speed pattern VP from the non-contact pullout height HH2 to the height HH1 which is likely to contact with the plate material is generated based on the distance D of transferring the plate material, in said pattern the motor speed not being zero when the distance D of transferring the plate material is under the predetermined distance, so that it can be rotated continuously so as not to stop the servomotor 19. Consequently, the load in accelerating and deaccelerating the speed is low and the accelerating and deaccelerating energy can be low. Thus, high hit rate and energy saving in the punch drive can be realized together.
The above predetermined distance is optional, however it cannot be set directly at distance value and it can be the distance predicted by setting the method of generating the motor speed pattern VP, for example.
Additionally, though the forming part is processed so as to protrude to the upper surface side in general in case of forming with the punch tool 6, the height HH1 which is likely to contact with the plate material and the non-contact pullout height HH2 are set in the position on the upper surface side of the plate material far from the position in the case of making holes as such a forming part is protruded.
The ram axis control means 33 can make the motor speed pattern VP according to the distance D of transferring the plate material a pattern that the acceleration in accelerating and deaccelerating is constant regardless of the distance D of transferring the plate material.
When the acceleration is constant, the load for calculating the motor speed pattern VP based on the distance D of transferring the plate material can be low by the punch drive means 9 and the high hit rate and energy saving can be realized by the simple control.
The motor speed pattern VP can have the constant speed pattern. When the motor speed pattern VP is made to be a curved line which switches from the deacceleration to the acceleration in V-shaped, the vibration and shock is generated in switching. It is not preferable to generate such vibration and shock when not punching as it is wasteful to generate the vibration etc. When having the constant speed pattern, such a rapid change in speed is not generated, the ram can move up and down smoothly when not punching and it excels at absorbing the vibration and shock.
The plate material transfer/punch motion control program of the present invention is provided for working a computer becoming a means for controlling the punch press as the next plate material transfer control means 32 and the ram axis control means 33.
The above punch press, making holes and/or forming with the punch tool 6, comprises the plate material transfer means 3 which transfers the plate material W and the punch drive means 9 which has the rotational/linear motion conversion mechanism 20 which converts the rotation of this servomotor 19 into the rise and fall of the ram 8 and moves the punch tool 6 up and down with the ram 8 by making the servomotor 19 as the driving force.
The plate material transfer control means 32 and the ram axis control means 33 composed by the above plate material transfer/punch motion control program have the means for having the following function.
The above plate material transfer control means 32 controls the plate material transfer means 3 so as to start to transfer the plate material when the punch tool 6 goes up to the pullout height HH2 not contact with the plate material W after punching the plate material W.
The ram axis control means 33 for controlling the punch drive means 9 rotates the servomotor 19 in one direction, controls such that the punch tool 6 reaches the height HH1 which is likely to contact with the plate material when the plate material transfer means 32 completes to transfer the plate material and the motor speed pattern VP when the punch tool 6 goes up from the non-contact pullout height HH2 to the height HH1 which is likely to contact with the plate material through the top dead center TDC is generated based on the distance D of transferring the plate material, in said pattern the motor speed not being zero if the distance D of transferring the plate material is under the predetermined distance. The motor speed pattern VP can have the constant speed pattern.
A recording medium of the present invention can be read by the computer, which records this plate material transfer/punch motion control program.
The plate material transfer/punch motion control program as in claim 6 of the present invention will be described with reference to FIG. 7. This plate material transfer/punch motion control program is executed in the computer which becomes a means for controlling the punch press along with a process program wherein a plate material transfer command for transferring the site of punching the plate material to the ram position is written in the block and it includes the following steps.
More specifically, this plate material transfer/punch motion control program comprises the steps of:
reading the look-ahead block that is the somethingth block from the running program as the control of the actual machine motion in the above process program (S2);
calculating the (expected) plate transfer distance of this read look-ahead block from the block (S3);
generating and memorizing the speed pattern in transferring the plate material of the look-ahead block from this calculated plate material transfer distance (S4);
calculating the plate material transfer time of the look-ahead block from the speed pattern in transferring this generated plate material (S6);
setting the motion time of the ram of the punch drive means in the look-ahead block from this calculated plate material transfer time (S7);
generating and memorizing the motor speed pattern of the ram motion when no contacting such that the non-contact ram motion that the ram reaches the height which is likely to contact with the plate material through the top dead center after the punch tool goes up to the pullout height not contact with the plate material after processing the plate material by rotating the servomotor driving the ram in one direction is implemented in the above calculated ram motion time and the motor speed is not zero when this ram motion time is under the set time (S8); and,
starting to transfer the plate material by the speed pattern in transferring the above plate material when the punch tool goes up to the pullout height after processing the plate material by using the generated speed pattern in transferring the plate material and the motor speed pattern in operating the ram when executing so as to control the actual machine motion by the look-aheadblock (S9xcx9cS11).
The recording medium as described in claim 7 of the present invention records the plate material transfer/punch motion control program as described in claim 6 of the present invention and can be read by the computer.